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  1. #1
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    dremeling/drilling chainrings

    Hey all, I'm looking to loose some weight on my new Race Face chainrings. Thought I might try dremeling and drilling them down a bit. Any suggestions as to where are the best places to take off weight?

    I was planning on more or less leaving the big ring alone so it would retain it's log smacking strength, and I've replaced the small ring with an Action-Tec Ti ring, so really, I'm mostly just looking to hack at the middl ring.

    Thanks,
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  2. #2
    Max
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    the middle ring is the last one to dremel down, as it shifts the chain both ways. steel granny gears are good for saving weight, but most weight is saved when trimming the outer ring. start from the inside and take care of the shifting ramps

    for more information, use the search function, there's a whole bunch of posts. try "chainrings" and "shave"


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  3. #3
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    Quote Originally Posted by FishMan473
    Hey all, I'm looking to loose some weight on my new Race Face chainrings. Thought I might try dremeling and drilling them down a bit. Any suggestions as to where are the best places to take off weight?

    I was planning on more or less leaving the big ring alone so it would retain it's log smacking strength, and I've replaced the small ring with an Action-Tec Ti ring, so really, I'm mostly just looking to hack at the middl ring.

    Thanks,
    Personally, I would take the 3 or 4 hours that you will spend ruining that perfectly good ring and go for a ride. You'll feel a lot better, plus you won't have to fed-ex overnight a new ring for your next ride. If you really need to lose a little weight that bad, trim your toenails and get a haircut!

  4. #4
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    hey it's Dondo again

    drilled chainring were all the rage around '75 or so. I recall seeing the guy whose wheel I was on in a crit completely fold over his big ring sprinting out a corner. Locked up his drivetrain, chain jammed his wheel somehow, he went down and I hopped over his back wheel and survived.
    Before you drill, weigh your ring. Then determine the number of holes, and their diameter, that you wish to drill, and using basic grade school math, you should be able to calculate your exact weight savings. Pi x radius squared for area, if I recall. Once you determine that the amount saved is insignificant, you can move on to other pursuits.
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  5. #5
    Boj
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    Race Face rings are very heavy so if you really want to save weight go for some lighter rings (when you wear them out) instead of shaving them.
    If in doubt - pedal harder!!!

  6. #6
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    big savings for free...

    Quote Originally Posted by FishMan473
    Hey all, I'm looking to loose some weight on my new Race Face chainrings. Thought I might try dremeling and drilling them down a bit. Any suggestions as to where are the best places to take off weight?

    I was planning on more or less leaving the big ring alone so it would retain it's log smacking strength, and I've replaced the small ring with an Action-Tec Ti ring, so really, I'm mostly just looking to hack at the middl ring.

    Thanks,
    forget about those race face rings as they are not worth investing several hours of work!
    as Max already said forget about the middle ring as there is only very little to be saved because of all the shifting ramps you don't want to touch. it's the big ring that has the most potential.

    but i would suggest you happily use your RF rings until they are worn and get lighter rings for the future. OR you start shaving the big ring just for fun and you will see how much time you spend and how little the savings are. it needs quite some time and the right tools to do it. a dremel isn't cutting fast enough. you need a stronger, bigger tool such as a drilling machine with a flexible axle and some serious metal cutters. that helps big time and makes shaving chainrings much easier. NO DRILLING! drilling saves only half as much and is also a pain in the a$$ to make look nice.

    here's a pic of my set of chainrings - 90g!
    Sugino Supershifter 42t: 49g
    Sugino Supershifter 32t: 32g
    custom 20t: 9g

    seeing these weights and comparing it to some regular chainring weights shows there is indeed some serious weight to be saved. especially if you use RF rings
    Extralite set: 16/32/62....110g
    Boone Ti set: 14/32/65....111g
    XT set: 20/40/80....140g
    Race Face set: 37/45/89....171g

    well - after all, it's weight savings you get for free if you have the time....
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  7. #7
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    from 98g to 70g
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  8. #8
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    Quote Originally Posted by Sonny
    from 98g to 70g
    Nice job Sonny - what tool(s) did you use to achieve this result? And how long did it take you?

  9. #9
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    Quote Originally Posted by top_ring
    Nice job Sonny - what tool(s) did you use to achieve this result? And how long did it take you?
    hand saw only - blade is look like a line, around 6~7 workings hours

  10. #10
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    such a weenie

    So I admit I'm being a weenie here and trying to shave a few grams.

    I guess what it comes down to is that this "upgrade" has become quite a mess. At first I thought I could replace my XTR chain rings with a 5-bolt spider and some rings to save cash, get a better gear ratio and maybe save some weight too. But things are not going well.

    I put everything on a scale and added everything up and the XTR rings weight a total of 211 g, and my Race Face/ Action-Tec set weight 243 g. That doesn't include the extra two chainring bolts needed, but it also doesn't include the missing 3.5 teeth off the XTR set and other lost material from four years of wear. I guess an extra 30 g isn't so bad...

    What's really bugging me now is that I'm finding out the spider I bought for $25 won't work with my cranks, and I need to get a $80 Shimano spider. So suddenly this cost of this "upgrade" is just a few dollars less then replacing my rings with new XTR rings, and it weighs more. At least I get away from those god-awful huge gear ratios. 24x32 granny gear, give me a break.

    I guess if I drill some holes in things and end up with a lighter chain ring set I'll feel like it's a worthwhile upgrade.

    And Sonny, it would be interesting to see a before picture of your chain ring. Mine is not the same model, but maybe I can learn from where you decided to take away material.
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  11. #11
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    Quote Originally Posted by FishMan473
    So I admit I'm being a weenie here and trying to shave a few grams.

    I guess what it comes down to is that this "upgrade" has become quite a mess. At first I thought I could replace my XTR chain rings with a 5-bolt spider and some rings to save cash, get a better gear ratio and maybe save some weight too. But things are not going well.

    I put everything on a scale and added everything up and the XTR rings weight a total of 211 g, and my Race Face/ Action-Tec set weight 243 g. That doesn't include the extra two chainring bolts needed, but it also doesn't include the missing 3.5 teeth off the XTR set and other lost material from four years of wear. I guess an extra 30 g isn't so bad...

    What's really bugging me now is that I'm finding out the spider I bought for $25 won't work with my cranks, and I need to get a $80 Shimano spider. So suddenly this cost of this "upgrade" is just a few dollars less then replacing my rings with new XTR rings, and it weighs more. At least I get away from those god-awful huge gear ratios. 24x32 granny gear, give me a break.

    I guess if I drill some holes in things and end up with a lighter chain ring set I'll feel like it's a worthwhile upgrade.

    And Sonny, it would be interesting to see a before picture of your chain ring. Mine is not the same model, but maybe I can learn from where you decided to take away material.
    detailed pics of my 42t Sugino Supershifter tuning:
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  12. #12
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    Hi, This is my old chainrings from Specialized StrongArm II (44 and 32T), they are worn but worked great. In this week I show picture in the scale. His structure is similar like Race Face, very heavy
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  13. #13
    Max
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    very nice work indeed. BUT: do these rings still shift? i suppose you also drilled away all shifting ramps. and what about stiffness?

    gosh, the teeth are really heavily worn


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  14. #14
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    Good job!

    Hi,
    I'm new on this forum. Here comes some pics of my drilled chainrings.
    First one is heavily drilled Stronglite 42t
    The second one is stock TA Specialites 42t and the third - TA Specialites drilled a little bit

    as you can see drilling saves only a little bit weight .... but drilled chainrings LOOK VERY COOL
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  15. #15
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    guys - be careful with drilling...

    Quote Originally Posted by doktoree
    Hi,
    I'm new on this forum. Here comes some pics of my drilled chainrings.
    First one is heavily drilled Stronglite 42t
    The second one is stock TA Specialites 42t and the third - TA Specialites drilled a little bit

    as you can see drilling saves only a little bit weight .... but drilled chainrings LOOK VERY COOL
    i see lots of places where your holes weaken the chainrings dramatically by leaving only millimeters of "meat". you don't want to weaken the chainring exactly where all the force goes through , right next to the spider.

    i also shaved a Specialized ring like the one shown above and mine weighs 54g. NO TOUCHING OF ANY SHIFTING RAMPS! you don't want to touch shifting ramps to retain perfect shifting. shaving saves more weight than drilling. i'm sure mine is lighter and your holes go straight through all those shifting ramps on the backside. see the backside of my ring...all shifting ramps are still untouched. it took me 5 minutes to shave that ring. but your drilled rings look great - kudos! it's not easy to have all holes aligned so nicely.
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  16. #16
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    Quote Originally Posted by nino
    i see lots of places where your holes weaken the chainrings dramatically by leaving only millimeters of "meat". you don't want to weaken the chainring exactly where all the force goes through , right next to the spider.

    i also shaved a Specialized ring like the one shown above and mine weighs 54g. NO TOUCHING OF ANY SHIFTING RAMPS! you don't want to touch shifting ramps to retain perfect shifting. shaving saves more weight than drilling. i'm sure mine is lighter and your holes go straight through all those shifting ramps on the backside. see the backside of my ring...all shifting ramps are still untouched. it took me 5 minutes to shave that ring. but your drilled rings look great - kudos! it's not easy to have all holes aligned so nicely.
    you're right. first of all: drilled chainring are weak. however I had no problems with my drilled chainrings at all. I'am XC and marathon racer, competing almost every weekend during the season. till now everything was OK.
    you're right that such drilling removed completely shifting ramps. I notice, however, it has no big influence to shifting. riding 2x9 combo you don't change gears as frequently as in 3x9. so shifting ramps REALLY dont't matter. that's MY opinion.

    Nino could you tell me HOW did you shave your chainrings. did you use a special dremmel maschine or ... just a hand file?

  17. #17
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    Quote Originally Posted by doktoree
    you're right. first of all: drilled chainring are weak. however I had no problems with my drilled chainrings at all. I'am XC and marathon racer, competing almost every weekend during the season. till now everything was OK.
    you're right that such drilling removed completely shifting ramps. I notice, however, it has no big influence to shifting. riding 2x9 combo you don't change gears as frequently as in 3x9. so shifting ramps REALLY dont't matter. that's MY opinion.

    Nino could you tell me HOW did you shave your chainrings. did you use a special dremmel maschine or ... just a hand file?
    here's my tools:
    as already said the drilling machine with flexible axle and big metal cutters is best and easiest to shave chunks of metal. that's the tool you see also in the picture where i shave my SLR saddles shell.
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  18. #18
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    FishMan473: i don't have the before picture.

    This is my tool.
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  19. #19
    Max
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    nino, i have a flexible axle for my dremel just like yours shown in the first pic. i also have the tool bits lying there (the rounded metal cutter attached to the axle, the sandpaper wheels and that pink sharpening tool which is rather useless cuz it falls apart after seconds) will those tools suffice? or do i need all the other cutters and the sandpaper-flap-wheel pictured in the next to the last shot? and what RPMs do you use when dremelling? mine has 6 levels, and i usually turn the RPM up to them 5th level.


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  20. #20
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    Good job!

    Quote Originally Posted by nino
    here's my tools:
    as already said the drilling machine with flexible axle and big metal cutters is best and easiest to shave chunks of metal. that's the tool you see also in the picture where i shave my SLR saddles shell.
    thanx very much Nino

  21. #21
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    Quote Originally Posted by Max
    nino, i have a flexible axle for my dremel just like yours shown in the first pic. i also have the tool bits lying there (the rounded metal cutter attached to the axle, the sandpaper wheels and that pink sharpening tool which is rather useless cuz it falls apart after seconds) will those tools suffice? or do i need all the other cutters and the sandpaper-flap-wheel pictured in the next to the last shot? and what RPMs do you use when dremelling? mine has 6 levels, and i usually turn the RPM up to them 5th level.
    use the biggest cutters you can! aluminium will clog tiny cutters quite easy as it gets melted and virtually sticks to the cutter making it useless.
    the big cutter you see i used on the SLR is the most efficient. the smaller bits are for the dremel i also have but it's just to polish or for minor work.
    my drilling machine has rather low speed (just 1 speed!). it's important to have a powerful machine rather than having a high speed one cuz as said the Al melts.

  22. #22
    Max
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    size DOES matter! *lol* side note: we got the same drilling machine at home. it was the first one my father got when he was young hehehe of course we now have a newer one....

    ok, will look out for one of those big cutters... but i doubt local hardware stores will carry them


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  23. #23
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    heavily drilled

    This is the weight of my heavily drilled Specialized chainrings 44T and 32T. They have worked great for all their life
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    loss of power...

    Quote Originally Posted by Filippo
    This is the weight of my heavily drilled Specialized chainrings 44T and 32T. They have worked great for all their life
    hey Filippo,
    those weights are cool BUT i have never seen as heavily worn chainrings as yours!!
    be aware that the efficiency of a brandnew chain on brandnew chainrings is about 99%. means if you have 100 watts only 99 get to the rear wheel, the rest is eaten away by friction and the created heat. now with a dirty chain the efficiency is already dropping several numbers and together with such worn teeth you are facing a significant powerloss. from what i remember its up to 10-20% of your power that gets eaten away in friction !!! so i strongly advise you change your chainrings, chain and cassette MUCH more frequently.

  25. #25
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    Quote Originally Posted by nino
    hey Filippo,
    those weights are cool BUT i have never seen as heavily worn chainrings as yours!!
    be aware that the efficiency of a brandnew chain on brandnew chainrings is about 99%. means if you have 100 watts only 99 get to the rear wheel, the rest is eaten away by friction and the created heat. now with a dirty chain the efficiency is already dropping several numbers and together with such worn teeth you are facing a significant powerloss. from what i remember its up to 10-20% of your power that gets eaten away in friction !!! so i strongly advise you change your chainrings, chain and cassette MUCH more frequently.
    I know about it. When my chainrings is worn I move it from my race bike to winter bike. In winter bike powerloss it not so important and I could heavily worn chainrings to end his life

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